Corona-discharge electrode system

ABSTRACT

A corona-discharge electrode system, especially for electrostatic precipitators and similar devices for the electrostatic separation of particles from a fluid stream, wherein the electrodes are secured to an upper carrying structure and a lower spacing structure. The electrodes, which are suspended from the upper structure, positively engage the same, e.g., via hooks, eyes or a clamping connection. Tensioning weights of a nonconducting material, preferably waterproof concrete, are removably secured to the lower ends of the electrodes and are provided with openings adapted to receive the spacing structure.

United States Patent 1191 Ertl et al. v 1

[ CORONA-DISCHARGE ELECTRODE SYSTEM [75] Inventors: Dietrich Ertl, Konigstein;

Horst-Gunter Eishold, Frankfurt am Main; Helmut Gilles, Bergen-Enkheim; Gunther Schmolling; Walter Steuernagel, both of Frankfurt am Main; Jurgen Nitz, Neu lsenburg, all of Germany [73] Assignee: Metallgesellschaft Aktiengesellscha'ft,

Frankfurt am Main, Germany [22] Filed: July 9, 1971 [21] Appl. No.: 161,070

[30] Foreign Application Priority Data 1.1, 13, 1970 Germany P 20 34 628.5 I

[52] US. Cl 55/146, 55/147, 55/148,

[58] Field of Search 55/146, 147, 148,

[56] References Cited UNITED STATES PATENTS 8/1912 Cottrell'et al.., 55/152 X 5/1955 Hull 55/147 X Jan. 8, 1974 2,711,224 6/1955 Herber 55/147 2,866,517 12/1958 Phyl 55/148 3,248,857 5/1966 We'indel et a1 55/118 3,485,011 12/1969 Archer et a1 55/151 X FOREIGN PATENTS OR APPLICATIONS 76,540 12/ 1948 Czechoslovakia 55/ 147 558,171 12/1943 Great Britain 55/148 OTHER PUBLICATIONS German Printed Application No. 1,158,044, printed Nov. 28, 1963 Primary Examiner-Dennis E. Talbert, Jr. Attorney-Karl F. Ross I 57] ABSTRACT A corona-discharge electrode system, especially for electrostatic precipitators and similar devices forthe electrostatic separation of particles from a fluid stream, wherein the electrodes are secured to an upper carrying structure and a lower spacing structure. The electrodes, which are suspended from the upper structure, positively engage the same, e.g., via hooks, eyes or a clamping connection. Tensioning weights of a nonconducting material, preferably waterproof concrete, are removably secured to the lower ends of the electrodes and are, provided with openings adapted to receive the spacing structure.

13 Claims, 14 Drawing Figures PATENTED m a 1914 3, 7 8 3 5 8 9 SHEET 1 0r 5 Dietrich ERTL et a1.

Attorney P'ATENTEDJAN 1914 3783589 //7 ran/0r:

Dietrich ERTL et a1.

Attorney PAIENTEDJAH 81974 SHEET 3 BF 6 Mrs/71m:

Dietrich ERTL et a1 1 CORONA-DISCHARGE ELECTRODE SYSTEM FIELD OF THE INVENTION BACKGROUND OF THE INVENTION In electrostatic precipitators, a particle-containing fluid stream generally traverses an array of coronadischarge electrodes which produce a local electrical charge picked up by the particles as the particles are entrained by the gas stream along the surfaces of oppositely charged collector plates, the particles adhered to these plates and are dislodged by rapping devices. The dust discharged from the plates is collected in bins therebelow. Such electrostatic precipitators have been used to clean industrial and'other gases and may be used for dusts of all types. v

Corona-discharge electrodes are an important part of these devices and have been provided in a variety of shapes and constructions; For the most part, however, they consist of plates, sheets, strips or foils supported at upper edges and extending in an upright configuration. Corona-discharge electrodes have been provided heretofore with a securing means at their upper ends and with weighted lower ends, the weights serving to maintain the corona-discharge electrodes under tension. Spacing means is provided in the form of .a lower frame in which the weights are guided. The disadvantages of such systems derived from the use of weights as tensioning and spacing members for coronadischarge electrodes; for example, when the latter are hooked onto the upper structure and are provided with weights guided only to a limited extent in a lower frame, the electrode is unstably positioned and is capable of moving toward and away from other parts of the precipitator or other electrodes, especially while generating a corona discharge. Furthermore, thin-sheet electrodes of this type are prone to deterioration by the electroerosive effect of the discharge so that the weights frequently break loose from the electrode or the weighted portion of the electrode breaks loose from the-upper supported portionwhereby the weights fall into the dust-collection bins and interfere with dust collection or endanger the precipitator or any dustprocessing means.

ls has also been proposed to use corona-discharge frames to support the electrodes in place of the weighted arrangements previously described. The frames generally are formed from tubes which are spanned by the corona-discharge electrodes under tension. Such frames are relatively expensive and difficult to manufacture or handle. In fact, the tubular frame is produced by welding, soldering, screwing connections or riveting as are the means for retaining the electrodes, and considerable care must be taken to insure wide-area contact between the corona-discharge electrode and the frame for optimal electrical transfer. When the frame is vibrated or jarred, e.g., as the dustcollecting plates are rapped, the connection between the corona-discharge electrode and the frame tends to loosen and produce an area of light contact in which arc-type discharge is sustained. Such discharge may cause spark erosion of the electrode material at the region at which it is joined to the frame with obvious disadvantages.

We also might note that corona-discharge frames have another disadvantage in that it is difficult-to make them sufficiently flat and resistant to distortion as to enable them to beused satisfactorily in large electrical precipitators having a height of say 12 to 15 meters. Also, especially with large corona .frames, the support tubes must be of a sufficiently large diameter to provide satisfactory stiffness; Almost invariably, :the tubes are wider than the thickness of the corona-discharge electrodes so that the discharge effect is reduced and dust streaks may appear at the gas outlet. Such dust streaks, of course, are ribbons of dust entrained by the fluid and not removed by the electrostatic precipitator. Finally, when the electrodes in the corona-discharge frame are damaged, they must be cut out or replaced otherwise at considerable expense, generally while the frame is retained in the precipitator. Repair of the precipitatoris thereby complicated.

I OBJECTS OF THE INVENTION It is the principal object of the present invention to provide an improved corona-discharge electrode system, especially -for an electrostatic precipitator, whereby the aforementioned disadvantages are obviated.

It is another object of the invention to provide a system of the character described in which the advantages of weighted-electrode arrangements can be maintained but disadvantages thereof, as enumerated above, can be avoided.

It is still another object of the present invention to provide a corona-discharge system for an electrostatic precipitator, the electrodes of which can be readily replaced, tensioned and straightened at any desired height.

Still another object of the invention is to provide an improved corona-discharge electrode arrangement which is less susceptible to electric erosion or damage,

in use.

' SUMMARY OF THE INVENTION These objects and others which will become apparent hereinafter are attained, in accordance with the present invention, with an arrangement in which the individual corona-discharge electrodes are positively locked to an upper carrying or support structure and have suspended at their lower ends tensioning weights of a nonconductive material and provided with horizontal openings for receiving a spacing structure. According to an important feature of this invention the spacing structure is a framework removably received in the aforementioned horizontal openings with freedom of at. least limited vertical movement of the spacing framework with respect to the tensioning weights. The term positively connected is here used to define the connection between the corona-discharge electrodes and the upper support structure allowing zero degrees of freedom of relative movement. In other words, the carrying structure and the upper end of the coronadischarge electrodes are so interconnected or locked together as to allow relative movement only in the form of a deflection of the electrodes. Y

The electrostatic precipitator in which the coronadischarge electrodes and spacing arrangement of the present invention are used may, except for the specific structure described herein, be of the type described in U.S. Pat. No. 3,354,617 in which the corona-discharge electrodes are ionizer wires. The arrangement of the present invention has an advantage over prior art systems for supporting the corona-discharge electrodes because the positive connection of each electrode with the support eliminates substantially entirely all contact resistance and thereby prevents arcing at the connection point which has hitherto characterized prior-art arrangements. Because the spacing structure lies in the horizontal openings of the tensioning weights which are of nonconducting material, no electrical connection is possible between the electrodes at the bottom end and electrical contact is confined to the positiveconnection structure of the upper end. Thus earlier arrangements, in which weights suspended from the corona-discharge electrodes serve to tension them, were characterized by spurious electrical currents or transients flowing through the spacing structure. Such spurious currents are now totally eliminated.

We have found, moreover, that it is important, if not essential, to provide the spacing structure (i.e., the frame removably received in the nonconductive weights) at least 3 cm below the lower ends of the corona-discharge electrodes to which the weights are anchored. In this case the weights may be provided with vertically extending slots forming the aforementioned openings and permitting the relative vertical movement of the weights and spacing frame, the weights also being formed with upwardly converging wedge-shaped passages in which the lower ends of the corona discharge electrodes are engaged after, for example, providing them with loops or the like. In this case, the spacing within each slot between an exposed end of the corona-discharge electrode and the upper surface of the sgtging frame is in excess of 3 cm. 'l" l i s arrange ment also elim inqes the small potential differences and voltage increase at selected electrodes which result from spark-over or charge-accumulations from other causes.

According to a more specific feature of the invention, the tensioning weights are composed of a waterproof concrete and are cast from this concrete composition. Substantially a hydraulic-cement concrete may be used according to the present invention and, in fact, the weights may be composed of any concrete of an electrically nonconductive or insulating nature which has heretofore been used to produce concrete bodies. Waterproofing additives such as silicates and substances which prevent the formation of condensate and conduction through condensate collected on the surfaces of the weights may also be added to the composition. The compositions may also be coated with condensate-excluding substances such as bitumens. Surprisingly, such concrete-composition weights have an advantage over metallic weights, although they are of lower specific gravity. Firstly they can be made easily and at lower cost and secondly are inherently conconductive whereas steel weights could have to be coated or otherwise made nonconductive. Furthermore, the breakdown potential of the concrete is high and there is no danger that spurious electric currents will pass between the corona-discharge electrodes and the weights. The concrete weights of the present invention have been found to be successful for tensioning electrodes having a length of to 12 m although the low specific gravity can also be counteracted by an increase in size.

In practical terms, it has been found that the cost of a steel weight is five times higher than that of a concrete weight of a similar mass and that the cost of a precipitator according to the present invention is substantially lower than that of a conventional, steel-weighted setup because thousands of weights are commonly employed.

The vertical slot, according to the invention, which forms in part the horizontal opening receiving the spacing frame, may be of generally rectangular configuration and may have an upwardly-tapering rectangular channel slightly wider than the thickness of the coronadischarge electrode to be received therein. The chan nel thus may serve to receive the bent eye-like lower end of the corona-discharge electrode strip. The bent eye of the lower end of the corona-discharge electrode can be inserted into upwardly tapering slots in such manner that the tensioning weight is supported by the corona-discharge electrode only (i.e., no other attachment device is provided) and the corona-discharge electrode is uniformly tensioned and straightened. To allow the bent eyes of the corona-discharge electrode to be received in the channels, which have minimum cross-sections less than the cross-section of the eye, we provide directly below the channel and on the opposite side of the opening or slot in which the spacer frame is received, a throughgoing bore. Thus, the coronadischarge electrode may simply be inserted through the channel and the bore until the lower end emerges from the side of the weight opposite the channel. The free end of the electrode projecting below the weight can then be bent into the eye-like configuration and drawn upwardly through the weight until it lodges in the tapering channel. The cross-section of the bore thus is in excess of the cross-section of the eye. Preferably, the eye is seated in the channel simply by allowing the weight to drop while the electrode is supported. If desired,the bore may be used to receive spacing pins of the spacing system, e.g., to prevent canting of the weights.

The slots and openings of the tensioning weights may have O-shaped vertical cross-sections and extend horizontally as noted earlier, preferably with a horizontal dimension that is a major fraction of the vertical dimension or is in excess thereof. In addition, the slots are provided with lateral passages through which the support structure may be inserted and by means of which the weights may be disengaged from the support structure. It is an important feature of the present invention that the support structure is retained solely by such weights and is suspended from the corona-discharge electrode and that no other means is provided for suspending or supporting this spacing structure. The entire weight of the spacing structure is carried by the coronadischarge electrodes so that it contributes to the tensioning or loading thereof. When the lateral passages of the weights are considered, the openings can be seen to have a C-cross-section. Where lateral openings are not provided, the spacing frame may be formed with flat arms or fingers which can be inserted endwise into the O-section slots and then rotated to lie flat therein.

We have also found it to be advantageous to provide the spacing structure with abutment means for preventing shifting of the weights along the bars of the spacing element. Thus when the weights are of a C-profile, this abutment means may be a pin projecting laterally into an opening of the weight. Where the horizontal opening is of O-cross-section, the arms may be provided with ridges or shoulders forming the abutment means.

The abutment or spacing pins of the first alternative preferably is permitted some freedom of vertical movement by, for example, shaping the opening in which the pin is accommodated as in a vertically elongated slot. The spacing structure can have a ladder-like configuration in which the latter spars each are received in a respective weight or are provided with arms received in such weights. A single strip may be used for connecting the spacer to two such weights and in this case the strips have a width in excess of that of the O-profile slots everywhere except in the region received in such slots. A ladder-like spacing structure thus may be used even when the slot forming the horizontal opening is of a closed configuration and the spars of a ladder-like spacer are disposed outside of the weights. In this case the strips form outriggers of the ladder-like spacer member.

According to still another feature of the invention, the spacer device comprises ladder-like spacing elements interconnected by cross webs of variable length. It has been found to be desirable, in compensating inaccuracies in the spacing established by setting the weights onto the spacer and vice versa, to use the adjustable cross webs to equalize the spacing and establish a rigid positioning of the weights in a horizontal plane.

For high electrical performance as an ionizer electrode, moreover, it has been found to be advantageous to provide the corona-discharge electrodes as serrated strips. Each of the electrodes thus may consist of a strip having toothlike formations along the edges so that the teeth face dust-collecting electrodes or plates at right angles thereto. Serrated strips of this character have a particularly high resistance to bending toward the dustcollecting electrodes, i.e., to transverse deflection. Best results with respect to the positive connection of the upper ends of the strip-like electrodes to the supporting structure are obtained when the anchor means comprises a pair of generally flat keys on wedges provided with mating bead and groove lying transversely to the wedging direction of the key. A single contact point is provided for the positive connection of the electrode to the support structure when the electrode is fitted between the wedges and the latter is driveninto a slot of the support structure. Alternatively, the serrated corona-discharge electrode is clamped between the teeth with a nut-'and-bolt arrangement, preferably via a widefaced sheet-metal clip engaging the electrode. The teeth may bear directly against flanks of the clip to prevent movement.

DESCRIPTION OF THE DRAWING The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing, in which:

FIG. 1 is a vertical elevational view, partly in diagrammatic form and partly in cross-section, illustrating the lower portion of a corona-discharge electrode spac- FIG. 5 is a side-elevational view of a weight as used in FIG. 4; i

FIG. 6 is a cross-sectional view taken along the line VI VI of FIGS; I I

FIG. 7 is a perspective view of the corona discharge electrodes and spacing system of FIGS. 1 3, parts being shown diagrammatically;

FIG. 8 is a perspective view similar to FIG. 7 but showing the embodiments of FIGS. 4 6;

FIG. 9 is a cross-sectional view illustrating the means for effecting a positive connection between the support and a serrated electrode, according to the invention;

FIG. 10 is a view taken generally along the line X X of FIG. 9;

FIG. 11 is a top plan view of the system of FIGS. 9 and 10; I

FIG. 12 is an elevational view showing the means for producing another positive connection between a serrated electrode and the upper carrying member of the electrostatic precipitator;

FIG. 13 is a front view thereof; and

FIG. 14 is a plan cross section showing this assembly.

SPECIFIC DESCRIPTION In the following description where reference is made to an electrostatic precipitator, except for the serrated electrodes, the upper anchoring structure and the weights and the spacing arrangement, it should be understood that the structure may be similar to that of US. Pat. No. 3,354,617.

In FIGS. 1 3, we have shown a portion of an electrostatic precipitator, according to the invention, which comprises the laterally spaced vertical dust-collecting electrodes or plates 1, which are fixed at their lower ends to respective beams 2. In accordance'with conventional techniques, a rapper may be provided to jolt thedust-collecting electrodes and cause the particles thereon to fall into a collecting bin. Between the dustcollecting electrodes, there are provided arrays of horizontally spaced vertical corona-discharge electrodes 3 in the form of serrated strips. The side edges and teeth of the corona-discharge electrodes face the collecting electrodes and extend at right angles to them. A typical corona-discharge electrode strip has been illustrated in FIG. 9 and can be seen to have teeth in the form of wedge-shaped points 3a, spaced apart along one end of the strip and pointed teeth 3b spaced along the opposite edge and disposed intermediate the teeth 3a. In FIGS. 7 and 8, the electrodes have been illustrated in the form of wires, but it will be understood that serrated or toothed electrodes are intended here as well.

The corona-discharge electrodes 3 are twisted through above and below the collecting electrodes, respectively for convenience in securing the upper ends of the electrodes to a supporting structure and for mounting the weights thereon. Each lower end of a corona-discharge electrode 3 is provided with an eye portion 4 in the form of a loop from which the tension weights 5 are suspended. The tensioning weights 5 are of generally prismatical configuration, as illustrated in FIGS. 1 3, with an upwardly convergent frustopyrimidal portion 5a above a rectangular parallelepipedal body 5b. Furthermore, the weights are composed of an electrically nonconductive or insulating concrete composition and are all-identical although the weights of adjacent rows of corona-discharge electrodes may be oriented mirrorsymmetrically as shown in FIG. 1.

Each weight is formed with an upwardly convergent channel 6 of rectangular cross-section, substantially in the vertical median plane of the weight and extending into a channel 7 having parallel walls and likewise of rectangular cross-section. The channel 7 is dimensioned to receive the strips 3 with slight clearance. The channels 6, 7 communicate with horizontally extending openings 8 which are vertically elongated and are of C- shaped cross-section to have the configuration of a vertical slot opening laterally at a window 8a close to the upper end of the slot. This slot or opening 8 has a length (in the vertical direction) of at least 3 cm in excess of the thickness of the spacer body to be received therein and the distance to which the strip projects from the channel into this opening, thereby ensuring a minimum spacing between the corona-discharge electrode and the spacer body of the 3 cm mentioned earlier. Directly below the channel 6, 7, the weight is formed with a bore 13 dimensioned to clear the corona-discharge electrode, even when the latter is formed with a loop as shown at 4. Furthermore, the wall of the weight opposite the window 8a is formed with a vertically elongated slot 12, the purpose of which will become apparent hereinafter.

The spacer structure consists of ladder-like elements, including spacing spars 9, pins projecting horizontally but laterally outwardly from the spacer, and rungs l1 interconnecting the spacer. One of these members may be tubular and can be welded together by conventional techniques. The width of the mouth 8a is sufficient to clear the spar 9 while the pins 10 are accommodated with clearance in the slots 12. Thus the spacers 9 are inserted in the C-shaped openings 8 so that the respective spacing pins enter the slot 12 and prevent lateral movement of the weights. The corona-discharge strip forming the electrode 3 is inserted through the upper slot 7 in the direction of arrow A until it passes out through the lower bore 13 so that the loop 4 can be formed thereon as shown by dot-dash lines 4' in FIG. 1. The loop 4 is therefrom retracted into the tensioning weight (arrow B) until engaged tightly by the wedge portion 6 of the upper channel. The system illustrated in FIGS. 1 3 allows the corona-discharge electrodes to elongate in the vertical direction without changing the spacing. If a corona-discharge electrode 3 should break, the tensioning weight falls until the upper end of the slot 8 rests upon the spar 9 so that the spacer struc ture 9, 10, 11 supports the weights, while being in turn supported solely thereon. The weightcannot fall into the precipitator bin. The array of electrodes has been illustrated in perspective view in FIG. 7, the ladder-like spacers being interconnected by cross webs 16 of variable length for compensating inaccuracies in the positioning of the spacer members. To permit adjustment of the effective length of the web 16, they may be provided on their opposite ends with threads of opposite senses, engaging in correspondingly threaded bores of the ladder elements or may be formed as tum-buckles. Rotation of the web 16 in one sense tends to spread the ladder structure while rotation of the webs in the opposite sense tends to draw them together.

In FIGS. 4 6 and 8, the generally prismatic cast concrete insulating weights are shown to have a pyramidal configuration and differ structurally from that of FIGS. 1 3 and 7 in only some respects. Each weight 105 is provided with a horizontal but vertically elongated opening 14 of O-cross-section communicating with a web-shaped channel 6 and a parallel-wall channel 7 as previously described. A bore 13 is provided in line with the channels 6 and 7 as previously described.

In this embodiment, however, the spacing structure comprises spars 9 and rungs 11, but the weights 105 are not mounted directly on the spars, but rather are mounted upon spacer strips 15 having the configuration illustrated. Bolts 15a connect the strips 15 to the spars 9 and the strips, in turn, are formed with cutouts 105a and 105b defining a region 1050 whose width corresponds to the horizontal width of the opening 14. Thus the weights may be slipped over the strips 15 or the latter inserted in the weights by arranging the weights and the strips so that the vertical axis of the opening 14 lies parallel to the strips. The strips 15 and the weights of them rotated relatively through to lodge the reduced-width section 150 in the slots 14 and permit the abutment shoulders d and 105e to prevent lateral displacement of these weights. As can be seen from FIG. 8, variable-effective-length struts 16 are provided to hold the ladder assemblies 9, 11 in a fixed relationship which can be adjusted to provide the desired space.

In FIGS. 9 11, we have shown a means for anchoring the corona-discharge electrode 3 to an upper support beam 17. The device of FIGS. 9 11, of course, can be used with either of the weighting structures already described. Similarly, each of the weighting structures can be used with either of the fastening devices for the upper ends of the electrode strips.

The beam 17 is provided with slots 19 adapted to receive a pair of wedges 18 which sandwich the electrode strip between them. The wedges 18 have complementary formations including a bead 18a on one of the wedges and a complementary recess 18b on the other wedge for engaging the electrode 3 by deformationthereof when the wedges are driven into the slot (see FIG. 11).

A similar positive connection for the upper end of the corona-discharge electrodes is formed by the arrangement of FIGS. 12 14 in which the electrode 3 is inserted into a thin wide-faced sheet-metal clip traversed by a threaded bolt 22 whose square shoulder 21 retains a screw without rotation in a support 23. The screw is tightened with a nut 25 and the points of the electrodes may rest against the square shank of the bolt as shown at 24 to prevent slipping of the electrode.

The improvementdefined and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the invention except as limited by the appended claims.

We claim:

1. A corona-discharge electrode system for an electrostatic precipitator, comprising:

a plurality of rows of vertically extending coronadischarge electrodes; carrying means anchoring the upper ends of said electrodes against movement;

respective tensioning weights of electrically insulating material suspended from each of said electrodes and maintaining same under tension, said weights being provided with horizontal openings; and

spacer means including a plurality of bars in fixed relationship, received in said openings for supporting said weights upon breakage of the respective electrodes and being supported, in turn, by the weights suspended from said electrodes, said horizontal openings being vertically elongated, said weights being provided at their upper ends with respective upwardly converging channels communicating with the respective opening and adapted to receive the respective electrode while gripping a formation provided on the lower end thereof, said weights being further provided with bores aligned with said channels and adapted to clear said formations.

2. The system defined in claim 1 wherein said weights are each composed of a waterproof concrete.

3. The system defined in claim 1 wherein said openings are generally of O-shape in vertical cross-section.

4. The system defined in claim 1 wherein said openings are generally of C-shape in vertical cross-section.

5. The system defined in claim 1, further comprising abutment means on said bars engageable with said weights for limiting transverse movement of said weights on said bars.

6. The system defined in claim 1 wherein said spacer means includes a plurality of ladder structures having spars and rungs forming said bars and means of variable effective lengths interconnecting said ladder structure.

7. The system defined in claim 1 wherein said electrodes are serrated strips provided with teeth along opposite edges adapted to face in the direction of respective dust-collector plates.

8. A corona-discharge electrode system for an electrostatic precipitator, comprising:

a plurality of rows of vertically extending coronadischarge electrodes;

carrying means anchoring the upper ends of said electrodes against movement; I respective tensioning weights of electrically insulating material suspended from each of said electrodes and maintaining same under tension,.said weights being provided with horizontal openings; and i spacer means including a plurality of bars in fixed relationship, received in said openings for supporting said weights upon breakage of the respective electrodes and being supported, in turn, by the weights suspended from said electrodes, said carrying means including a carrying bar provided with a plurality of slots each assigned to one of said electrodes and a pair of wedges receivable in each slot for clamping the respective electrode between them, said wedges being provided with complementary formations deformingly engaging the respective electrode.

9. The system defined in claim 8 wherein said electrodes are serrated strips provided with teeth along opposite edges adapted to face in the direction of respective dust-collector plates.

10. The system defined in claim 8 wherein said weights are each composed of a waterproof concrete.

11. A corona-discharge electrode system for an electrostatic precipitator, comprising:

a plurality of rows of vertically extending coronadischarge electrodes;

carrying means anchoring the upper ends of said electrodes against movement;

.respective tensioning weights of electrically insulating material suspended from each of said electrodes and maintaining same under tension, said weights being provided with horizontal openings;

and

spacer means including a plurality of bars in fixed relationship, received in said openings for supporting said weights upon breakage of the respective electrodes and being supported, in turn, by the weights suspended from said electrodes,

said carrying means including a respective sheet metal clip receiving each of said electrodes, a nonrotatable bolt transversing said clip and provided with a polygonalshank engaging the electrode, and means for securing said bolt to a support.

12. The system defined in claim 11 wherein said electrodes are serrated strips provided with teeth along opposite edges adapted to face in the direction of respective dust-collector plates.

13. The system defined in claim 11 wherein said weights are each composed of a waterproof concrete. 

1. A corona-discharge electrode system for an electrostatic precipitator, comprising: a plurality of rows of vertically extending corona-discharge electrodes; carrying means anchoring the upper ends of said electrodes against movement; respective tensioning weights of electrically insulating material suspended from each of said electrodes and maintaining same under tension, said weights being provided with horizontal openings; and spacer means including a plurality of bars in fixed relationship, received in said openings for supporting said weights upon breakage of the respective electrodes and being supported, in turn, by the weights suspended from said electrodes, said horizontal openings being vertically elongated, said weights being provided at their upper ends with respective upwardly converging channels communicating with the respective opening and adapted to receive the respective electrode while gripping a formation provided on the lower end thereof, said weights being further provided with bores aligned with said channels and adapted to clear said formations.
 2. The system defined in claim 1 wherein said weights are each composed of a waterproof concrete.
 3. The system defined in claim 1 wherein said openings are generally of O-shape in vertical cross-section.
 4. The system defined in claim 1 wherein said openings are generally of C-shape in vertical cross-section.
 5. The system defined in claim 1, further comprising abutment means on said bars engageable with said weights for limiting transverse movement of said weights on said bars.
 6. The system defined in claim 1 wherein said spacer means includes a plurality of ladder structures having spars and rungs forming said bars and means of variable effective lengths interconnecting said ladder structure.
 7. The system defined in claim 1 wherein said electrodes are serrated strips provided with teeth along opposite edges adapted to face in the direction of respective dust-collector plates.
 8. A corona-discharge electrode system for an electrostatic precipitator, comprising: a plurality of rows of vertically extending corona-discharge electrodes; carrying means anchoring the upper ends of said electrodes against movement; respective tensioning weights of electrically insulating material suspended from each of said electrodes and maintaining same under tension, said weights being provided with horizontal openings; and spacer means including a plurality of bars in fixed relationship, received in said openings for supporting said weights upon breakage of the respective electrodes and being supported, in turn, by the weights suspended from said electrodes, said carrying means including a carrying bar provided with a plurality of slots each assigned to one of said electrodes and a pair of wedges receivable in each slot for clamping the respective electrode between them, said wedges being provided with complementary formations deformingly engaging the respective electrode.
 9. The system defined in claim 8 wherein said electrodes are serrated strips provided with teeth along opposite edges adapted to face in the direction of respective dust-collector plates.
 10. The system defined in claim 8 wherein said weights are each composed of a waterproof concrete.
 11. A corona-discharge electrode system for an electrostatic precipitator, comprising: a plurality of rows of vertically extending corona-discharge electrodes; carrying means anchoring the upper ends of said electrodes against movement; respective tensioning weights of electrically insulating material suspended from each of said electrodes and maintaining same under tension, said weights being provided with horizontal openings; and spacer means including a plurality of bars in fixed relationship, received in said openings for supporting said weights upon breakage of the respective electrodes and being supported, in turn, by the weights suspended from said electrodes, said carrying means including a respective sheet metal clip receiving each of said electrodes, a nonrotatable bolt transversing said clip and provided with a polygonal shank engaging the electrode, and means for securing said bolt to a support.
 12. The system defined in claim 11 wherein said electrodes are serrated strips provided with teeth along opposite edges adapted to face in the direction of respective dust-collector plates.
 13. The system defined in claim 11 wherein said weights are each composed of a waterproof concrete. 